Question: 3 markers cost $5.37. Which equation would help determine the cost of 11 markers?
Solution: There are several equations that could help determine the cost, each with a slightly different approach. We can write the fact that 3 markers cost $5.37 as a proportion: $\dfrac{3}{\$5.37}$ Let $x$ represent the unknown cost of 11 markers. Since 11 markers cost $x$ , we have the following proportion: $\dfrac{11}{x}$ The cost changes along with the number of markers purchased, and so the two proportions are equivalent. $\dfrac{3}{\$5.37} = \dfrac{11}{x}$